Epoxides are important intermediates for the manufacturing of numerous products. They are preferably prepared by the oxidation of the corresponding olefins. It is desirable to use hydrogen peroxide as the oxidant, as it leaves only water after the reaction. However, hydrogen peroxide is not reactive enough and has to be activated for the oxidation of olefins.
A known way of activation is the reaction of hydrogen peroxide with a carboxylic acid to give a peroxycarboxylic acid, which is capable of oxidizing olefins to epoxides. These processes have the disadvantage, that the carboxylic acid, which is used as an auxiliary, has to be separated from the reaction product or discarded with the aqueous effluent after the reaction, which leads to additional cost.
Another known way of activation is the use of a catalyst for the oxygen transfer. These processes carry additional cost for the catalyst. In addition, these catalysts and the transition metals on which they are usually based on tend to pollute the aqueous effluents and have to be removed from the aqueous waste with considerable expenditure.
Both ways of activation also require substantial safety measures, as the decomposition of hydrogen peroxide can liberate molecular oxygen, which can form flammable vapors with the olefin or the usually required solvent. Therefore the gas phase over the reaction mixture has to be inertized.
Thus, it is the object of the present invention to provide a process which does not have the above exhibited disadvantages.